Hydrogen Production Startup via PSA and Reformer Coordination
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Solution Overview
Problem
The existing hydrogen production facilities with catalytic steam-hydrocarbon reformers and pressure swing adsorption units face challenges in quickly and efficiently starting up after maintenance, leading to increased consumption of feedstock and fuel during the startup phase.
Innovation Solution
A process that involves concurrent startup of the catalytic steam-hydrocarbon reformer and pressure swing adsorption unit, utilizing nitrogen purging to prepare the adsorption beds and adjusting hydrogen pressures within specific target ranges to minimize fuel consumption and reduce startup time, while also incorporating nitrogen and steam purging to manage combustible gas concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sequential startup procedure is used, then safety is improved, but startup time and fuel consumption increase
Solution Approach 1:
The PSA unit is started up in advance before the reformer unit, preparing the adsorption beds and establishing operational parameters beforehand. This preliminary action allows the PSA unit to be ready to receive reformate immediately when the reformer starts up, enabling concurrent operation and reducing overall startup time while maintaining safety through pre-established safety protocols
Solution Approach 2:
The startup procedure transitions from static sequential steps to dynamic concurrent operation. The reformer and PSA unit operate simultaneously with coordinated control, allowing the system to adapt real-time parameters such as reformate flow rates and PSA cycle timing to optimize both safety and startup efficiency
2Ease of operation
If sequential startup procedure is used, then operational control is improved, but fuel consumption increases
Solution Approach 1:
The reformer operates continuously during startup without interruption to heat the catalyst or complete warmup cycles. Reformate is continuously fed to the PSA unit which processes it throughout the startup period, eliminating idle time where fuel is consumed but no productive output is generated, thereby reducing overall fuel consumption while maintaining operational control
Solution Approach 2:
The PSA unit autonomously manages its own startup sequence and operational parameters, independently preparing adsorption beds and establishing cycle timing without requiring step-by-step manual intervention. This self-service capability reduces the complexity of coordinated control while optimizing fuel utilization during the startup phase
3Reliability
If nitrogen purging is extended, then safety is improved, but startup time increases
Solution Approach 1:
Nitrogen serves as an intermediary gas that facilitates safe startup by temporarily displacing oxygen from the system during critical phases. The nitrogen purging is strategically applied only where and when needed - specifically during PSA bed preparation and reformer warmup - rather than throughout the entire system continuously, thus maintaining safety while minimizing time loss
Solution Approach 2:
Nitrogen purging is applied partially rather than excessively - used selectively in specific zones and time periods during startup when safety requires it, rather than continuously throughout the entire system. This partial application achieves adequate safety margins while significantly reducing the total purging time required
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces the time and fuel required for startup, ensuring efficient and safe operation by optimizing the purging processes and concurrent startup sequences, thereby minimizing feedstock and fuel consumption.
Implementation Method 1
a pressure swing adsorption unit production state wherein the pressure swing adsorption unit separates a pressure swing adsorption unit feed gas formed from at least a portion of the reformate withdrawn from the plurality of catalyst-containing reformer tubes of the catalytic steam-hydrocarbon reformer undergoing the catalytic steam-hydrocarbon reformer production state to produce the H2-containing product and the by-product gas
Implementation Method 2
purging the plurality of adsorption beds with N2 to provide a N2 concentration in each of the plurality of adsorption beds greater than 96 volume % N2, or greater than 99.6 volume % N2, or greater than 99.96 volume % N2
Implementation Method 3
subsequently purging the plurality of adsorption beds with H2 to provide a H2 concentration in each of the plurality of adsorption beds greater than 85 volume % H2 or greater than 95 volume % H2 or greater than 99 volume % H2
Implementation Method 4
a reformer feed gas mixture is introduced into the plurality of catalyst-containing reformer tubes, the reformer feed gas mixture is reacted in a reforming reaction under reaction conditions effective to form a reformate comprising H2, CO, CH4, and H2O
Implementation Method 5
a fuel is combusted with an oxidant gas in the reformer furnace external to the plurality of catalyst-containing tubes
Data Source
Figure 1
AI summary
Process for the production of a H2-containing product in a hydrogen production facility comprising a catalytic steam-hydrocarbon reformer and a pressure swing adsorption unit. The process comprises a catalytic steam-hydrocarbon reformer shutdown mode, a pressure swing adsorption unit shutdown mode, a pressure swing adsorption unit maintenance state, a pressure swing adsorption unit startup mode, and a catalytic steam-hydrocarbon reformer startup mode. The pressure swing adsorption unit startup mode comprises purging the adsorption beds with N2, then purging the adsorption beds with H2, and then adjusting the pressure of the H2 in the adsorption beds to within defined target pressure ranges.